When a silver halide color photographic material is subjected to color development after being exposed to light, the resulting oxidized aromatic primary amine developing agent reacts with a dye-forming coupler to form a color image. In general, this process uses color reproduction by subtractive process. In order to reproduce blue, green, and red, color images of yellow, magenta, and cyan, which are their respective complementary colors, are formed. For the formation of a cyan color image, a phenol derivative or naphthol derivative is often used as a coupler. In color photography, a color-forming coupler is added to a developing solution or incorporated in a light-sensitive photographic emulsion layer or other color image-forming layers. Such a color-forming coupler reacts with an oxidized form of a color developing agent formed upon development to form a nondiffusive dye.
The reaction of a coupler with a color developing agent takes place at the active position of the coupler. The coupler containing a hydrogen atom at the active position is a tetraequivalent coupler, i.e., coupler which stoichiometrically needs 4 moles of a silver halide containing development nuclei to form 1 mole of dye. On the other hand, the coupler containing a releasable group as anion at the active position is a diequivalent coupler, i.e., coupler which stoichiometrically needs only 2 moles of silver halide containing development nuclei to form 1 mole of dye. Accordingly, as compared to tetraequivalent coupler, the use of such a diequivalent coupler can reduce the amount of silver halide required to be contained in the light-sensitive layer, providing a thinner film. This enables a reduction in the time for processing of the light-sensitive material and improves the sharpness of color images formed.
As such a cyan dye-forming coupler there has been heretofore used a phenol or naphthol coupler. In particular, a naphthol coupler is advantageous in that the dye produced thereby has a maximum absorption (.lambda..sub.max) of a longer wavelength. This means that the coupler absorbs less light in the green region, thus providing excellent color reproducibility. Furthermore, a large number of couplers excellent in color-forming properties have been found and put into practical use, particularly as color negative light-sensitive material.
However, most of such naphthol couplers, particularly 2-alkylcarbamoyl-1-naphthol coupler, or such phenol couplers are disadvantageous in that when processed with a fatigued bleaching or blix bath or a bleaching or blix bath having a weak oxidizing power in a bleaching or blix process in color development processings, they cannot provide a sufficient color image density. This phenomenon is thought to be partially attributable to discoloration of the cyan dye by ferrous ions produced bleaching or blix process.
In order to eliminate such a disadvantage, phenol couplers containing a ureido group at the 2-position and a carboamido group at the 5-position have been proposed. Examples of such phenol couplers are disclosed in U.S. Pat. Nos. 4,333,999, 4,451,559, 4,465,766, and 4,427,767 and Japanese Patent Application (OPI) Nos. 65134/81, 204543/82, 204544/82, 204545/82, 33249/83, and 33250/83 (the term "OPI" as used herein means an "unexamined published application"). These couplers are advantageous in that they are less susceptible to discoloration of color images by ferrous ions and that color images formed thereby are fast to light, heat, and moisture. However, on the other hand, these couplers are also disadvantageous in that the color images formed thereby absorb more light in the green region, thus providing poor color reproduction. Furthermore, since these couplers do not have sufficient color formation properties, they are not always suitable for the recent high sensitivity light-sensitive materials excellent in image quality.
2-arylcarbamoyl-1-naphthol couplers as described in U.S. Pat. No. 3,488,193 are advantageous in that color images formed thereby absorb less light in the green region, that the color images thus formed are less susceptible to discoloration by ferrous ions, and that they are excellent in color formation properties. As a 2-arylcarbamoyl-1-naphthol coupler there have been heretofore known those containing straight-chain alkoxy groups as the substituent or ballast group (also called anti-diffusion group) for the aryl group at the 2-position of 1-naphthol as described in U.S. Pat. No. 3,488,193. However, these couplers are disadvantageous in that color images formed thereby have a maximum absorption wavelength (.lambda..sub.max) shifted to remarkably short wavelength in a higher color density region or higher dye density region. This increases the absorption of light in the green region, deteriorating the color reproducibility.
Furthermore, coupler containing a branched alkoxy group as an anti-diffusion group are disclosed in Japanese Patent Application (OPI) No. 3031/73 corresponding to U.S. Pat. No. 3,892,576. However, neither description nor suggestion of application to 2-arylcarbamoyl-1-naphthol couplers is given in the above patent. The object of the coupler is to improve solubility and dispersibility of couplers.